Automatic screw driver



M. R. HUTCHISON, JR 2,327,796

AUTOMATIC SCREW DRIVER 3 Sheets-Sheet 1 Filed June 24, 1941 ATTORNE YS Aug. 24, 1943.

Aug. 24, 1943. M. R. HUTCHISON, JR

AUTOMATIC SCREW DRIVER 3 Sheets-Sheet 5 Filed June 24, 1941 M/YIe/"RHZ/zCh/S0/7Jr INVENTOR ATTORNEYS H a 2mm s 5 M 8 Q, 7 H I Lrl 9 v 5 I W1 s I: I 5 5 2 8 4 0 2 I 10 w v 1 w 4 v 4 a F L 1 Q W44 7 W 2 a m l "w k 7 0, N7 5 w M a 0 0 5 U I a M i Z 3 M w w a u 4 6 w.

Patented Aug. 24, 1943 AUTOIVIATIC SCREW DRIVER Miller E. Hutchison, 312, Rochester, N. Y., assignor to Eastman Kodak Company, Rochester, N. 1., a corporation of New Jersey Application June 24, 1941, Serial No. 399,472

9 Claims. ((31.144-32) This invention relates to automatic screw drivers. One object of my invention is to provide a screw driver designed to rapidly apply screws to work. Another object is to provide a screw driver adapted for use with screw sticks in which the screws are integrally formed, the head of one screw being connected to the threaded portion of another screw, by a narrow frangible neck. Another object is to provide a screw driver with an automatic screw advancer 'so that after applying one screw to work, a second screw will be positioned for application to work without further attention from an operator. Another object is to speed up and to increase the accuracy of applying screws to work and to provide a driver which will reduce to a minimum the nervous strain of applying screws, particularly small screws, to work. Other objects will appear from the following specification the novel features being particularly pointed out in the claims at the end thereof.

Coming now to the drawings in which like reference characters denote like parts throug out:

Fig. 1 is a top plan view of the automatic screw driver,

Fig. 2 is a frontv elevation of the automatic screw driver,

Fig. 3 is a sectional view of the automatic screw driver taken on the line 3-3 of Fig. 1.

Fig. 4 is a side elevation of the automatic screw driver,

Fig. 5 is a view similar to Fig. 3 showing the relation of the various parts during the first portion of the cycle of operation in which the feed .35 plunger picks up the next screw on the stick as the chassis is moved toward the work,

Fig. 6 is a view also similar to Fig. 3 in'which the chassis has been moved to a position in which the screw is in contact with the work and the switch has been closed to start the motor drive,

Fig. 7 is a sectional view taken on the line 1-1 of Fig. 5, r

Fig. 8 is a sectional view taken on the line 8-8 of Fig. 7,

Fig. 9 is a perspective view of the nose of the driver showing driving aperture,

Fig. 10 is a view showing the operating lever connected to a treadle, and

Fig. 11 is a view of a screw stick as may be used in the automatic screw driver.

My invention comprises broadly providing an automatic screw driver in which applying a screw to work automatically advances another screw 55 into a screw driving position without any attention on the part-of an operator. My improved screw driver utilizes screw sticks of the type shown in Fig. 11, in which each screw S has a narrow neck N connecting it to the next adjacent screw. The necks N are of such an area that they may be twisted off when the end screw is properly seated by a torque applied to the next adjacent screw. Such screw sticks are shown in my patent for Screw sticks No. 2,247,499,

granted July 1, 1941.

As shown in Fig. 3, the various parts comprising the automatic screw driver are in a. position of rest with a screw ES extending from the nose of the screw driver ready for the beginning of the cycle of operation. The plate In which is to be secured to the plate I! is shown merely by way of an example of typical work, designated broadly as W into which screws are to be seated.

The plates Ill and II are placed below the screw 1 driver in a predetermined aligned position and the aperture l2 in the plate Ill aligned with the tapped hole lit in the plate II. This may be accomplished by any suitable jig or fixture, depending on the work to be secured together. Aside from the placing of the work under the screw driver, the only other function that the operator must perform aside from occasionally loading the screw driver is the operating of the foot treadle M (Fig. 10) that is pivoted on the supporting member I5 and connected to the op erating lever IS.

The operating lever l6 Fig. 10 is fixed by the screw 33 to a shaft l'l carried by the frame I8 and has an extending arm I9 with an car 20 that moves a chassis 2| carrying a screw driver pointing in a downward direction toward the work, as will be more fully described hereinafter. portion 22 on which is mounted the motor 23 and an upwardly extending column 24, in which is mounted the screw driver, having horizontally extending lugs 25 into which the bushings 21 and 28 are screwed to serve as bearings for the guide rods 29 carried by the frame 8. The guide rods 29 are fixed in the bearing portions 30 of the frame l8 by the set screws 3i. The chassis 2| is supported with respect to the frame l8 by the coil springs 32 surrounding the guide rods 29 between the lugs 25 and the bearing portions 30 of the frame l8.

Fixedto the other end of the shaft ll by the screw 33 is an arm l9 similar to arm l9 and having a similar ear 20'. Both the ears 20 and 20' rest on the lugs 25 so that any movement of The chassis 2| comprises a base plate.

the treadle l4 rotates the operating lever IS, the shaft l1 and the arms I9 and 9 causing the ears and 26 to exert a pressure on the lugs against the action of the springs 32, thereby moving the chassis downward.

As the treadle I4 is moved downward, the chassis 2| through the operating lever 6 and the arm l9 and I9 is also moved downward, thereby compressing the springs 32. During this movement the plunger spring expands holding the cap 36 against the stop nuts 31 on the guide rods 29. The cap 36 is threaded to receive the feed plunger extension 38, which is locked against any slippage by the nut 39, and has extensions 40 in which bushings 4| for the guide rods 29 arelocated. During this travel of the treadle I4, the feed plunger 42 moves upward relative to the barrel 43 of the screw driver until the shoulder 44 on the feed plunger extension 38 abuts against the bottom of the feed plunger extension stop 45 which is threaded into the barrel 43.

The screw stick 46 is placed in the opening 41 4 in the feed plunger 42 and held in position by the spring 48 secured in the nose 49. The nose 49 is carried by a sleeve 50 having a central opening to receive the feed plunger 42 and is pressed into the nose 49 and locked with the set screw 50' so that, in effect, the two members form a single unit which can be threaded into the barrel 43.

The nose 49, as shown in Figs. 7 and 9 has a hexagonal portion 65 corresponding in shape to the heads of the screws on the screw stick for obtaining a'positive driving connection. It will be readily understood, that the shape of this opening. is dependent on the screws being driven. Two slots 66 and 61 are adjacent the hexagonal portion 65 for the holding spring 48 and the advancing spring 5|, and the opening 68 is provided for the feed plunger 42. Thus the head of the end screw ES to be driven into work lies outside configuration 65 and will be driven into work solely through the narrow neck N so that when properly seated the neck N will be'twisted or broken oil. The advancing spring 5| is brazed at one end into the slot 52 in the feed plunger 42, and as the feed plunger 42 moves relative to the chassis 2|, the advancing spring moves out of engagement with the screw as shown in Fig. 3, to fall in behind the next screw as shown in Fig. 5'.

Further pressure applied to the treadle l4, will move the chassis downward until the screw extending from the nose 49 is in contact with the work, as shown in Fig. 6. This movement of the chassis 2| will compress the spring 32 still more and a clearance between the stop nuts 31 and the bushings 4| will be obtained. As still further pressure is applied to the treadle l4, the force exerted on the screw stick 46 will be transmitted through the spring 48 and 5| to the screw driver causing it to move relative to the .chassis 2| and compressing the spring 53. The relativ movement of the screw driver with respect to the chassis 2| closes the Micro-Switch 54 fastened to the motor 23 by the bracket 55. This switch is of the type in which the circuit is opened by depressing the button, which is spring pressed closed. The switch is operated by the arm 56 hinged at 51 to the L-shaped plate 58 and has a yoke opposite the hinged end which engages the underside of the adjustable lock nut 59 screwed onto the feed plunger extension stop 45.

The Micro-Switch 54 is normally held in open circuit position by the arm 56, through action of spring 53 on the driver however, when the spring 53 is compressed and the lock nut 59 with the Serial No. 399,119, filed June screw driver moves relative to the chassis 2| the switch is closed completing an open circuit and the motor is started. The motor drives the screw driver through the gears 60, GI and 62 which is pressed into the reduced end of the barrel 43.

The barrel 43 is inserted in any suitable bearin afl'ording radial support while permitting axial movement such as the needle bearings 63 in the column 24 of the chassis 2|.

As the pressure'is still further increased on the treadle l4, the chassis 2| and the screw driver are moved bodily downward increasing the clearance between the bushings 4| and the stop nuts 31, until the screw is seated when further rotation of the driver will break off the driven screw from the screw stick 46. If the material is such that a roughened area occurs at the break, momentary continued contact of the fractured areas quickly smooths and burnishes this area, as is more fully described'in my copending application for method of Burnishing screw stick heads,

After the screw has been driven into-the work and broken ed, the pressure on the treadle I4 is released allowing the spring 53 to expand and open the switch 54 by depressing the button 64 with the arm 56, thereby shutting off the motor 23. Further release of the pressure on the treadle |4, allows the spring 32 to return the bushings 4| carried by the cap 36 against the stop nuts 31. When the pedal is fully released the spring 32 overcomes the plunger spring 35 and causes the feed plunger 42to move relative to the chassis 2|, thereby advancing the screw stick so that the next screw is positioned for driving.

From the above description it will appear that with a screw driver constructed in accordance with this preferred embodiment of my invention an operator has just one operation to drive in screws-lower the foot treadle. Of course he must occasionally load the driver-with a fresh stick of screws but this is easily and rapidly done by entering a new stick in the open top I39 and thrusting it downwardly until it engages springs 48 and 5|. The operation of driving screws into work with this automatic screw driver can be accomplished more rapidly and easily thru the usual type of riveting operation. Obviously my invention is not confined to the single form shown and described as a preferred embodiment of my invention and I consider as within the scope of my invention all such formsas may come within the terms of the appended claims.

I claim:

1. In an automatic screw driving machine adapted for use with screw sticks comprising a plurality of integral screws having a narrow neck connecting the head of one screw to the threaded shank of the next adjacent screw. the combination with a frame, a chassis slidably mounted on the frame to move to and from work, a screw stick holder adapted to drive the successive screws of the screw stick by turning a screw into work by the head of a next adjacent screw carried by the chassis, a. motor, driving connections between the motor and screw stick holder vancing mechanism and the frame movable by the spring for moving the screw advancing mechanism to advance a screw each time the spring is released.

2. In an automatic screw driving machine by the former, movable connections between the' frame and chassis on which the latter may move ,to and from work, a spring for normally holding the chassis away from work, bearings for revolubly and slidably carrying the screw stick holder on the chassis, a screw advancingmechanism slidably mounted in the screw stick holder, means,

adapted to contact with the slidably mounted screw advancing mechanism and connected to the frame whereby the screw advancing mechanism may be actuated when the chassis is moved away from the work by the chassis moving spring after a screw has been driven into the work.

3. In an automatic screw driving machine adapted for use with screw sticks comprisinga plurality of integral screws having a narrow neck connecting the head of one screw to the threaded shank of the next adjacent screw, the combination with a frame, a chassis slidably mounted on the frame to move to and from work, a screw stick holder adapted to drive the successive screws of the screw stick by turning a screw into work by the head of a next adjacent screw car-,

a. screw with work, a screw advancing mechanism slidably mounted in the screw stick holder, a plunger adapted to contact with the screw advancing mechanism in the screw stick holder and connected to the frame, said plunger contacting with the screw advancing member each time the spring moves the chassison the frame to its normal position after contacting a screw with work, said movement of the chassis and movement of the screw stick holder axially on the chassis breaking the circuit through the Micro-Switch.

5. A mechanism for driving an end screw of a stick of screws irrwhich each screw is connected to the next adjacent screw by a narrow neck and including in combination, a frame, a chassis movably mounted thereon, a spring normally holding the chassis away' from work, a screw driver slidably and rotatably carried by the chassis forming a lost motion'connection therewith, means for turning the screw driver, a spring tending to hold the screw driver toward work to ried by the chassis, a motor, driving connec tions between the motor and screw stick holder for turning the latter, bearings on the chassis revoluble and slidably supporting the screw stick holder, a screw advancing mechanism carried by the screw stick holder, a spring between the frame and chassis positioned to be compressed by moving said chassis toward work, operable connection between the screw advancing mechanism and the frame movable by the spring for moving the screw advancing mechanism to advance a screw each time the spring is released, and a Micro-Switch, a circuit including said switch and said motor, the switch being positioned to make a circuit when the screw stick holder moves axially in contacting a screw with work and means for sliding the screw stick holder relative to the chassis to break the circuit after a screw has been driven into work.

4. In an automatic screw driving machine adapted for use with screw sticks comprising a plurality of integral screws having a narrow neck connecting the head of one screw to the threaded shank of the next adjacent screw, the combination with a frame of a chassis movably mounted thereon, a screw stick holder adapted to drive successive screws of the screw stick by turning a screw into work by the head of a next adjacent screw, a spring normally holding the chassis in a rest position on the frame, a motor, driving connections between the motor and the screw stick holder for tuming the latter by the former, bearings for revolubly and slidably carrying the screw stick holder on the chassis, a Micro-Switch, a circuit including said switch and said motor, the switch being positioned to make a circuit when the screw stick holder moves axially on the chassis in contacting receive a screw whereby said spring may be compressed as the screw is driven into work moving the screw driver in its lost motion connection, a screw advancing mechanism carried by the screw driver, connections between the screw advancing mechanism and the frame including a plunger axially -arranged with respect to the screw advancing mechanism and adapted to contact therewith, and means including said first-mentionedspring adapted-to hold the chassis in a raised position-for operating the screw advancing mechanism each time the spring moves the chassis to a position raised from the work after a screw has been driven into work.

6. A mechanism for driving an end screw of a stick of screws each of which is connected to the next adjacent screw by a narrow neck and including, in combination, a frame, a chassis movably mounted on the frame, hinged members between the chassis and the frame, a spring normally holding the chassis in a normal raised position, a screw driver slidably and rotatably carried by the chassis forming a 1051; motion connection therewith, means for turning the screw driver, a second spring tending to hold the screw driver toward the work and positioned to be compressed as a screw is driven into work while moving the screw driver in its lost motion connection, a screw advancing mechanism carried by the screw driver, aplunger, connections between the plunger and the frame, said plunger lying in the path of and adapted to contact with the screw advancing mechanism, said spring for normally holding the chassis in a raised position being adapted to actuate the screw advancing mechanism each time said spring raises the chassis to a normal position, and a foot treadle connected to the chassis for operating the hinged member for moving the screw driver to bring the screw into contact with work.

7. A mechanism for driving an end screw of a screw stick, in which each screw is connected to the next adjacent screw by a narrow neck, solely through said narrow neck, including, in combination a frame, 'a foot treadle pivotally attached thereto, arms carried'by the pivotal support for the treadle and movable thereby, a chassis movably mounted on the frame, a chasis spring normally holding the chassis in a. raised position, the chassis being engaged by the arms for movement thereby, a screw driver slidably and rotatably mounted on the chassis, a spring tending to hold the screw driver toward work to receive a screw, a motor carried by the chassis, driving connections between the motor and screw driver for turning the screw driver by the motor, a switch, and a circuit including the switch and motor, means for operating the switch through movement of the screw driver relative to the chassis when a screw is contacted with work by moving the chassis through the foot treadle, and mechanism for advancing a screw automatically as said screw driver moves under the impulse of the chassis spring for normally holding the chassis in a raised position as the chassis is moved from the work.

8. A mechanism for driving an end screw of a screw stick, in which each screw is connected to the next adjacent screw by a narrow neck solely through said narrow neck, including, in combination a frame, a foot treadle pivotally attached thereto, arms carried by the pivotal support for the treadle and movable thereby, a chassis, a movable mount carried by the frame and comprising a slideway and carriage between the frame and chassis on which the latter may slide, spring means for holding the chassis in a raised position, the chassis being engaged by the arms for movement thereby when the foot treadle is moved, a screw driver rotatably and slidably mounted on the chassis, a spring tending to move the screw driver toward work to receive a screw, a motor carried by the chassis, driving connections between the motor and screw driver for turning the screw driver by the motor, a switch, and a circuit including the switch and motor, means for operating the switch through movement of the screw driver relative to the chassis when a screw is contacted with work by moving the chassis through the foot treadle, and mechanism for advancing a screw automatically as said screw driver moves under the impulse of the first mentioned spring as the chassis is moved from the work.

9. A mechanism for driving an end screw 01 a screw stick, in which each screw is connected to the next adjacent screw by a narrow neck solely through said narrow neck,'including, in combination, a frame, a foot treadle pivotally attached thereto, arms carried by the pivotal support for the treadle and movable thereby, a chassis, a movable mount carried by the frame and comprising a slideway and carriage between the frame and chassis on which the latter may slide, spring means for holding the chassis in a raised position, the chassis being engaged by the arms for movement thereby when the foot 'treadle is moved, a screw driver rotatably and slidably mounted on the chassis, a spring tending to move the screw driver toward work to receive a screw, a motor carried by the chassis, driving connections between the motor and screw driver for turning the screw driver by the motor, a switch, and a circuit including the switch and motor, means for operating the switch through movement of the screw driver relative to the chassis when a screw is contacted with work by moving the chassis through the foot treadle. and mechanism for advancing a screw automatically as, said screw driver moves under the impulse of the first mentioned spring as the chassis is moved from the work, comprising a. plunger for advancing the screw stick one step, a plunger advancing spring, and means including the chassis spring and fixed stop for the screw driver for causing a screw to be advanced in the screw driver when pressure on the foot treadle is released.

MILLER R. HUTCHISON, JR. 

